from ctypes import *
import array
import gc
import unittest
class X(Structure):
_fields_ = [("c_int", c_int)]
init_called = False
def __init__(self):
self._init_called = True
class Test(unittest.TestCase):
def test_from_buffer(self):
a = array.array("i", range(16))
x = (c_int * 16).from_buffer(a)
y = X.from_buffer(a)
self.assertEqual(y.c_int, a[0])
self.assertFalse(y.init_called)
self.assertEqual(x[:], a.tolist())
a[0], a[-1] = 200, -200
self.assertEqual(x[:], a.tolist())
self.assertRaises(BufferError, a.append, 100)
self.assertRaises(BufferError, a.pop)
del x; del y; gc.collect(); gc.collect(); gc.collect()
a.append(100)
a.pop()
x = (c_int * 16).from_buffer(a)
self.assertIn(a, [obj.obj if isinstance(obj, memoryview) else obj
for obj in x._objects.values()])
expected = x[:]
del a; gc.collect(); gc.collect(); gc.collect()
self.assertEqual(x[:], expected)
with self.assertRaisesRegex(TypeError, "not writable"):
(c_char * 16).from_buffer(b"a" * 16)
with self.assertRaisesRegex(TypeError, "not writable"):
(c_char * 16).from_buffer(memoryview(b"a" * 16))
with self.assertRaisesRegex(TypeError, "not C contiguous"):
(c_char * 16).from_buffer(memoryview(bytearray(b"a" * 16))[::-1])
msg = "does not have the buffer interface"
with self.assertRaisesRegex(TypeError, msg):
(c_char * 16).from_buffer("a" * 16)
def test_fortran_contiguous(self):
try:
import _testbuffer
except ImportError as err:
self.skipTest(str(err))
flags = _testbuffer.ND_WRITABLE | _testbuffer.ND_FORTRAN
array = _testbuffer.ndarray(
[97] * 16, format="B", shape=[4, 4], flags=flags)
with self.assertRaisesRegex(TypeError, "not C contiguous"):
(c_char * 16).from_buffer(array)
array = memoryview(array)
self.assertTrue(array.f_contiguous)
self.assertFalse(array.c_contiguous)
with self.assertRaisesRegex(TypeError, "not C contiguous"):
(c_char * 16).from_buffer(array)
def test_from_buffer_with_offset(self):
a = array.array("i", range(16))
x = (c_int * 15).from_buffer(a, sizeof(c_int))
self.assertEqual(x[:], a.tolist()[1:])
with self.assertRaises(ValueError):
c_int.from_buffer(a, -1)
with self.assertRaises(ValueError):
(c_int * 16).from_buffer(a, sizeof(c_int))
with self.assertRaises(ValueError):
(c_int * 1).from_buffer(a, 16 * sizeof(c_int))
def test_from_buffer_memoryview(self):
a = [c_char.from_buffer(memoryview(bytearray(b'a')))]
a.append(a)
del a
gc.collect() # Should not crash
def test_from_buffer_copy(self):
a = array.array("i", range(16))
x = (c_int * 16).from_buffer_copy(a)
y = X.from_buffer_copy(a)
self.assertEqual(y.c_int, a[0])
self.assertFalse(y.init_called)
self.assertEqual(x[:], list(range(16)))
a[0], a[-1] = 200, -200
self.assertEqual(x[:], list(range(16)))
a.append(100)
self.assertEqual(x[:], list(range(16)))
self.assertEqual(x._objects, None)
del a; gc.collect(); gc.collect(); gc.collect()
self.assertEqual(x[:], list(range(16)))
x = (c_char * 16).from_buffer_copy(b"a" * 16)
self.assertEqual(x[:], b"a" * 16)
with self.assertRaises(TypeError):
(c_char * 16).from_buffer_copy("a" * 16)
def test_from_buffer_copy_with_offset(self):
a = array.array("i", range(16))
x = (c_int * 15).from_buffer_copy(a, sizeof(c_int))
self.assertEqual(x[:], a.tolist()[1:])
with self.assertRaises(ValueError):
c_int.from_buffer_copy(a, -1)
with self.assertRaises(ValueError):
(c_int * 16).from_buffer_copy(a, sizeof(c_int))
with self.assertRaises(ValueError):
(c_int * 1).from_buffer_copy(a, 16 * sizeof(c_int))
if __name__ == '__main__':
unittest.main()
